/*
* #!
* Ontopia Engine
* #-
* Copyright (C) 2001 - 2013 The Ontopia Project
* #-
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* !#
*/
package net.ontopia.topicmaps.query.impl.rdbms;
import java.util.List;
import net.ontopia.persistence.query.jdo.JDOEquals;
import net.ontopia.persistence.query.jdo.JDOValueIF;
import net.ontopia.topicmaps.query.core.InvalidQueryException;
import net.ontopia.topicmaps.query.parser.Variable;
/**
* INTERNAL: Implements the '=' predicate.
*/
public class EqualsPredicate
extends net.ontopia.topicmaps.query.impl.basic.EqualsPredicate
implements JDOPredicateIF {
// --- JDOPredicateIF implementation
public boolean isRecursive() {
return false;
}
public void prescan(QueryBuilder builder, List arguments) {
}
public boolean buildQuery(QueryBuilder builder, List expressions, List arguments)
throws InvalidQueryException {
// Interpret arguments
Object[] args = arguments.toArray();
// Cannot execute if arguments are variables of type java.lang.Object
if (args[0] instanceof Variable) {
Class vt1 = builder.getVariableType(((Variable)args[0]).getName());
if (Object.class.equals(vt1)) return false;
}
if (args[1] instanceof Variable) {
Class vt2 = builder.getVariableType(((Variable)args[1]).getName());
if (Object.class.equals(vt2)) return false;
}
// TOLOG: $LEFT == $RIGHT
JDOValueIF jv_left = builder.createJDOValue(args[0]);
JDOValueIF jv_right = builder.createJDOValue(args[1]);
// JDOQL: LEFT == RIGHT
expressions.add(new JDOEquals(jv_left, jv_right));
return true;
}
}